Widescreen experiment: native render size via dxwrapper, classic menus

- mods/widescreen: redirect the world view's reads of the 1024.0/768.0
  constants and the 3D ortho extents to our variables; render size =
  monitor; relocate the world view's tile draw list (1750 entries, no
  bounds check) into an enlarged object (16384 entries).
- mods/dxwrapper: route DirectDraw through dxwrapper (Dd7to9, D3D9) since
  Windows' D3D7 cannot render to targets larger than 2048; fix the game's
  device info GUID pointer that dxwrapper's enumeration leaves invalid.
  Pinned release fetched by CMake (hash-checked), installed next to the DLL.
- Main menu (UI thread) and loading screen render in a 1024x768 viewport
  and are presented scaled ("classic" layout); in-game uses the full size.
- re/patch: verified code patches (operand redirect, push immediates,
  displacements) and startup hooks; build.ps1/CMake download fixes.

In-game view untested yet; HUD still at the top-left.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/re/patch.h

@@ -0,0 +1,33 @@
+#pragma once
+// Verified in-place patches of sacred.exe code. Every function checks that the
+// bytes it expects are present before writing, logs and refuses otherwise.
+
+#include <cstddef>
+#include <cstdint>
+
+namespace re {
+
+bool WriteCode(uint32_t address, const void* bytes, size_t size);
+
+// The instruction at `instruction` has the absolute memory operand `from`
+// (e.g. `fmul st, dword ptr [from]`); make it read `to` instead.
+bool RedirectOperand(uint32_t instruction, uint32_t from, const void* to);
+
+// Replace a 32-bit displacement/immediate `from` inside the instruction at
+// `instruction` by `to` (e.g. a struct field offset in `[ebp+ecx*8+3FF2Ch]`).
+bool PatchInstructionDword(uint32_t instruction, uint32_t from, uint32_t to);
+
+// `push imm32` (68 xx xx xx xx) at `instruction`: replace `expected` by `value`.
+bool PatchPushImm32(uint32_t instruction, uint32_t expected, uint32_t value);
+
+// Code that must run once at startup, after the hooks are installed.
+class StartupRegistration {
+public:
+    StartupRegistration(const char* name, void (*function)());
+};
+void RunStartupFunctions();
+
+} // namespace re
+
+#define RE_STARTUP(name, function) \
+    static ::re::StartupRegistration name##_startup(#name, &function)